1. Field of the Invention
The present invention relates to a novel speed adjustment device adapted for a sprinkler used to water gardens and lawns, which can vary the operation frequency of the splatter arm of a sprinkler so as to make the water sprinkled in a more even and effective manner.
2. Description of the Prior Art
As shown in FIG. 1, the prior art sprinkler adapted for watering gardens and lawns is equipped with a securing base 10 coupled to a water source pipe with a rotatable body 11 mounted thereon; and a limiting stick 12 used to adjust the angle of rotation of the rotatable body 11; and a water discharging hole communicating with the securing base 10; a pivotal splatter arm 13 pivotally mounted to the body 11 with the front end thereof disposed at a distance from the water discharging hole; and a bias spring 14 connecting the splatter arm 13 to the rotatable body 11; and some means to make the rotatable body spin whereby the pivotal splatter arm 13 actuated by the bias spring 14 and the pressure of the discharged water can be pivoted back and forth and make the discharged water sprinkled.
This prior sprinkler can operate in a good manner but the pivotal splatter arm works only at a fixed frequency, because of the tension of the bias spring being invariable, making the sprinkling effect less satisfactory.